54 LANDS OF THE ARID REGION OF THE UNITED STATES. 
Second District—In the San Francisco Region a rainy season is still 
more definitely marked, but occurs at a different time of year. It will be 
seen by Tables III and VIII that no rain falls in summer, while the winter 
months receive 60 per cent. of the annual precipitation, and the spring 25 
per cent. The general yearly rainfalt of the district is only about 16 
inches, but by this remarkable concentration a period of five months is 
made to receive 13 inches. The winter temperature of the district is no less 
remarkable, and supplies the remaining condition essential to agriculture. 
Frosts are rare, and in the valleys all the precipitation has the form of rain. 
The nine stations which afford the rainfall records given above show a 
mean spring temperature of 57° (see Table IX). Thirteen inches of rain 
coming in a frostless winter and spring have been found sufficient for 
remunerative agriculture 
TABLE IX.—Mean temperatures, by seasons, for the San Francisco Region. 
Mean temperatures, in degrees Fahr. | 
Sika Extent of | | 
record. | | 
Spring. | Summer.| Autumn.) Winter. Year. | 
| 
- ie —- = 
Y. i. | | | 
AGE VA EI EG Shssocosnen dan toonesridon Sonnac sn sneer, 8 6 55 57 | 60 54 57 | 
PAmpal alan datas seen eee seul cece Ss ee MO meee Gail 58 GE aaa 52 58 
| Benicia Barracks.......- 15 7 58 67 62 49 59. 
ortiMiller=:=>-22------- 7 6 64 86 67 49 67 
SMomt SONG anor iene 10 11 55 59 58 52 56 | 
\Monterey:=c2o05- -es-e-o- meee Ssce ss 12 5 55 | 60 | 57 50 55 I 
Shoramentorsnameote cine ae 14 0 BO eee vdke ay 9262 48 60 | 
San Francisco; Presidio 19 0 54 | 57 57 50 55 
|| (eth eR en 5s eGeor nine soe rasnccic eaomanosssoesossscoce 11 2 55 58 58 50 55 | 
| INT eects Se en tons IR SEED | RE aS sv | Ga 60 50 58 
The same winter maximum of rainfall is characteristic of the whole 
Pacific coast. The Region of the Lower Columbia, with an average rain- 
fall of 46 inches, receives 47 per cent. of it in winter and 24 per cent. in 
spring. Southward on the coast, Drum Barracks (near Los Angeles) and 
San Diego receive more than half their rain in winter, but as the whole 
amount is only 9 inches agriculture is not benefited. The eastern bases 
of the Sierra Nevada and Cascade Range exhibit the winter maximum of 
rainfall, and this feature can be traced eastward in Idaho and Nevada, but 
